My invention relates to easy-open containers and in particular container ends which might be most easily pictured as pull top cans. My invention is directed to containers wherein the pull top is not detachable. In particular, my invention is useful for containers wherein the container end with the pull top is manufactured of a polymeric plastic, typically a thermoplastic molding compound wherein the entire assembly may be injection molded in one piece.
Most present pull top ends have a top section that either completely separates from the can or is merely bent back along a fold line. These tear strips can easily work loose from the can, increase litter and a safety hazard to the user or to the person stepping on the discarded piece. The tops of cans are typically constructed of aluminum or steel and leave sharp edges on the tear strip as well as the can. These edges are a safety hazard to children or even adults as these parts must be handled with utmost care.
The easy-open cans have enjoyed ready acceptance for such can products as beverages, including carbonated beverages, such as beer, soft drinks and the like, as well as other products such as puddings, fruit juice and the like. These easy opening cans have not yet been used for granular products such as sugar, spices, drink mixes and other such items, possibly because of the inability to produce such an item from a polymeric plastic in a construction that will not cause significant difficulties.
While metal will generally take a permanent set when substantially folded, most plastics will not react in the same fashion and will tend to return to their original shape. This is particularly true with polymeric plastics such as polyethylene, polypropylene, polyvinyl chloride, acrylonitrile styrene polymers and copolymers and the like. Thus, if a pull tab were constructed of a like polymeric material, it would tend to return to the opening from which it was torn. The user would have to hold the tab back out of the way causing great inconvenience and loss of effectiveness. A typical easy opening container is described in U.S. Pat. No. 3,437,227 to H. A. Peyser. This opener pulls toward the center of the can, but leaves the jagged tear strip in place. Another typical end assembly is that easy open container described in U.S. Pat. No. 4,108,302 to Richard A. Patterson. Another easy open can is described in U.S. Pat. No. 3,900,128 to Omar L. Brown.
Some container tops have directed attention to holding the tear strip out of the way such as in U.S. Pat. No. 3,386,613 to B. J. Traynor and U.S. Pat. No. 3,847,300 to Lyle E. Waters. Both of these devices attach over or onto the rim of the can top. A plastic cover for press-in cover cans is described in U.S. Pat. No. 3,246,792 to T. G. W. Brackmann et al with tongue or flap means to oppose the tendancy of the elastic hinge strip to bring the cover back to closed position. A snap on container lip with fold back drink opening is described in U.S. Pat. No. 3,994,411 to Walter Elfelt wherein a flap is inserted into a slit in the removable lid snapped on to a plastic or paper container.
None of these devices satisfy the above needs nor the objects listed hereinbelow.
It is an object of this invention to provide a container end that may be constructed of materials that will not leave a cutting or jagged edge, but will solve the problems associated with such materials that will not take a permanent set when substantially folded.
It is an object of this invention to provide a pull top tear strip construction that will remain out of the user's way after opening, but may be reclosed.
It is an additional object of this invention to provide a container end, such as a can top in which the entire top including the tear strip, the pull tab and a hold down device may be molded in one piece from a thermoplastic polymer.
It is an additional object of this invention to hold down mechanism which is simple and inexpensive which will prevent a tear strip molded of a thermoplastic material tendancy to return to the opening away from that opening.
It is a further object of this invention to provide a hold down system to prevent the tear strip from yielding to the tendancy to return to the opening without breaching the integrity of the can interior, at least until the tear strip has been torn from its position sealing the can.
It is a specific object of this invention to provide a pull tab which may be easily grasped and lifted before pulling on the tear strip to form the opening in the container.
It is an object of this invention to provide an easy open container end in a container in which the end is sealed to the container to protect the contents of the container from adulteration, spoilage and leaking.
It is particular object of this invention to provide a tear strip in the container end that may be easily started and ripped to form the pour opening.
It is an additional object of this invention to provide a container end useful in sealing and providing an easy open end construction for sanitized containers, such as vials and ampules.